Catalytic Oxidative Coupling of Methane: Heterogeneous or Homogeneous Reaction?

Direct valorization of methane via oxidative coupling (OCM) is an encouraging alternative to conventional oil-based processes for the production light hydrocarbons (ethane and ethylene). Abundant, inexpensive simple oxides such as MgO La2O3 possess ability selectively activate methane. However, during OCM, selective conversion ethane following dehydrogenation ethylene are threatened by thermodynamically favored partial total oxidation reactions form CO CO2, respectively. With aid spatially resolved operando analysis temperature gas concentration along catalytic bed, we demonstrate relevance highly exothermic reaction paths developed in phase, i.e., homogeneous reaction, OCM conditions at front largely determining C2 yield obtained on those systems. new insights provided gradients redefine positive effect promoters (Li, Sr), which enhance influence catalyst surfaces. The recognized suppression leading undesired COx, thus limiting formation hotspots driving toward desired products.